Fan fold or Z-fold tractor paper which has been used in a variety of printer applications over the past several years has a certain initial and inherent memory before being fed through a printer. If this memory could somehow be retained at the output of the printer, it would tend to correctly and uniformly refold and stack the paper in an output paper tray or bin. Unfortunately, this inherent memory is, to a significant degree, lost when the paper is processed through the printer. This is a result of the processed paper being exposed to heat and pressure within the printer and to inertia therein as a result of the paper being subjected to periodic variations in paper speed.
Because of the latter phenomenon, the paper develops a tendency to fold in an output paper tray or bin in a direction opposite to the direction of memory or bias which was initially inherent in the paper upon receipt from the manufacturer. This improper folding is caused by the fact that the paper tends to drop straight down vertically into an output paper tray or bin instead of being projected from a paper exit port of the printer at a desired angle toward one side of the output paper tray. This vertical dropping motion will in turn frequently cause the paper to buckle up in the output tray or bin and become extremely resistant to uniform refolding and stacking. It is the solution to this problem to which the present invention is directed.